Are people at risk?
Fortunately, the risk of being hit by space debris falling back to Earth is extremely small. The Earth’s surface is enormous, and most of it is uninhabited.
Debris left in orbit below 600 kilometres normally falls back to Earth within ten years, while that left at 800 kilometres can stay there for decades or more. When it does fall back to Earth, most debris does not survive the intense heat of re-entry into Earth’s atmosphere. Objects that do survive are most likely to fall into oceans or on to sparsely populated areas.
Over the past 40 years, an average of one piece of space debris has fallen back to Earth every day, although there is no record of any serious injury or significant property damage occurring as a result of returning debris.
British National Space Centre (2004), Space debris
What can be done to reduce space debris?